Azo dyestuffs and their production



Patented Apr. 5, 1938 UNITED STATES 2,112,920 PATENT OFFIE AZO DYESTUFFSAND THEIR PRODUCTION Mordecai Mendoza and Francis Leslie Rose,Manchester, England, assignors to Imperial Chemical Industries Limited,a corporation of Great Britain No Drawing. Original application June 20,1934,

Serial No. 731,568. Divided and this application September 2, 1937,Serial No. 162,222. In Great Britain June 23, 1933 4 Claims.

Z X l I NQNH1 Y 10 (EH where X stands for 0001-1, OCH3, 0r OCzHs and ofY and Z one stands for hydrogen, Br, C1, CH3,

C2H5, OCHs, OC2H5, N02, or SOBH and the other for hydrogen. When X=OCH3,or 002135 the diamino-azo-benzene may be obtained by combiningdiazotized 5-amino-N-acetyl-anthranilic acid or diazotized5-nitro-3-amino-benzoic acid and an o-alkoxy-w-sulpho-ethyl-aniline(which may if desired carry substituents appropriate to give thesubstituted diamino azo benzenes formulated above) the w-sulpho-methyland acetyl groups being removed.

When X=COOH and Y and Z both=H the diamino-azo-benzene isazo-anthranilic acid, a hitherto unknown dyestufi intermediate which maybe obtained as described in U. S. Patent No. 2,049,510.

When the tetrazotized diamino-azo-benzenes are coupled with one or twomolecules of a phenol or naphthol, the hydroxyl group being in orthoposition to the azo linkage the new dyestufis are also suitable for theproduction of copper-containing azo dyes in substance, for example byafter-treating them with copper salts in substance.

The following examples in which parts and percentages are by Weightillustrate but do not limit the invention.

EXAMPLE I Trisazo dyestufis from 4,4'-didmino-3-methory-3-carboatyazo-benzene and I-naphthoZ-al-sulphonic acid tion is formedfrom which the dyestuff is isolated by adding common salt, filtering anddrying. It yields bluish-violet shades on cotton which becomeviolet-grey on after-coppering.

Production of 4,4-diamino-3'-meth0o:y-3-carbowyaao-benzene used asstarting material above 19.4 parts of 5-amino-N-acetyl-anthranilic acidare dissolved in parts of water with the aid of 36 parts of hydrochloricacid (26%) and diazotized at 0 to 5 C. by addition of 6.9 parts ofsodium nitrite. To the diazo compound, which is mainly out of solution,sufficient sodium acetate is added to remove mineral acidity and thesuspension is then added, with stirring, to a solution of 23.9 parts ofthe sodium salt of 2-methoxy-wsulpho-methyl-aniline in 200 parts ofwater. Coupling, which gives a yellowish brown suspension is allowed tocomplete itself in about 24 hours and the suspension is then madedefinitely caustic alkaline by the addition of parts of caustic soda lye(34%) and boiled under a reflux condenser for about 4 hours. At the endof this period hydrolysis of the coupling product is complete and thesodium salt of 4,4'-diamino-3'- methoxy-S-carboxyazobenzene is produced.The free acid is then precipitated by addition of suificient acetic acidto impart a definite acid reaction to litmus, filtered off, dried andground. It forms a dark yellowish-brown powder which is moderatelysoluble in dilute mineral acids and easily soluble in more concentratedacids and in alkalies.

Alternative method for the production of 4,4'-dz'-amino-3-metho:cy-3-carboxy-azo-benzene In a mixture of 150 parts ofwater and 10.5

parts of caustic soda lye, there are dissolved in the given order 18.2parts of 6-nitro-3-aminobenzoic acid and 6.9 parts of sodium nitrite.The solution is then added with stirring to a mixture of 40 parts ofwater, 34.5 parts of concentrated hydrochloric acid (36%) and 100 partsof ice. The diazo solution so obtained is added with stirring to asolution of 23.9 parts of the sodium salt of2-methoxy-w-sulpho-methyl-aniline in 200 parts of water and 20 parts ofcalcined sodium carbonate. Coupling is complete in 8 hours.

IIhe resulting yellow-brown solution of the nitroazo compound is reducedat 50 C. during 2 hours by the slow addition of 36 parts of sodiumsulphide nonahydrate crystals. 17.5 parts of caustic soda lye are thenadded and the strong- 1y alkaline mixture is gently boiled for 2 hoursin an open vessel. At the end of this period hydrolysis of thew-sulphomethyl group is complete and the4,4-diamino-3'-methoxy-3-carboxy-azo benzene is precipitated with aceticacid and isolated in the manner described above.

EXAMPLE II Treatment of the dyestufi of Example I with copper sulphate'7 5.6 parts of the dyestuff obtained as in Example I above by couplingthe tetrazo compound from 28.6 parts of 4,4-diamino-3-methoxy-3carboxy-azo-benzene with 44.8 parts of l-naphthol-4-sulphonic acid aredissolved in 500 parts of water with the addition of sufficient sodiumcarbonate to make the solution neutral to litmus paper. 50 parts ofcopper sulphate crystals are then added and the mixture is boiled undera reflux condenser for 3 to 4 hours. It is then made faintly alkaline bythe addition of sodium carbonate and filtered while hot. On cooling, thecopper complex is precipitated by means of common salt. It dyes cottondirectly in violetgrey shades.

EXAMPLE III Trzsazo dye from 4,4-diamino-3'-methoxy-3-carboazy-azo-benzene and 1-amino-8-naphthol- 2,4-disulphom'c acid(ZS-acid) A tetrazo solution obtained as in Example I from 28.6 parts of4,4-diamino-3-methoxy-3- carboxy-azo-benzene is added with stirring to asolution of 68.2 parts of the mono-sodium salt of1-amino-8-naphthol-2,4-disulphonic acid (23- acid) in 250 parts of watercontaining 75 parts of calcined sodium carbonate. The coupling so lutionis deep blue in color and the dyestuff is precipitated when coupling iscomplete, by adding common salt after removing excess alkalinity. Itdyes cotton in bright blue shades which are converted to greenish-blueon after-coppering.

Very similar direct and after-coppered shades are produced by thedyestufi which is obtained when the equivalent amount ofl-amino8-naphthol-3,6-disulphonic acid is used as the couplingcomponent.

The corresponding dyestuffs obtained in similar manner by coupling with47 .8 parts of (a) 2- amino-8-naphtho1-S-sulphonic acid or (b) 47.8parts of 2-amino-5-naphthol7-sulphonic acid to the tetrazo compoundprepared from 28.6 parts of 4,4-diamino-3-methoxy-3-carboxy-azo-benzenedye cotton in blackish-brown shades which are converted tobrownish-black on after-treatment with copper sulphate and in royal blueshades which become slightly greener when aftercoppered.

EXAMPLE IV Trisazo dye from 4,4-diamino-3-methoxy-3- carboxy-azo-benzeneand 1-phenyZ-3-methyl- 5-pyraeolone A tetrazo solution obtained as inExample I above from 28.6 parts of4,4'-diamino-3"methoxy-B-carboxy-azo-benzene is added with stir- ,ringat 5-10 C. to a solution of 34.8 parts of EXAMPLE V Trisazo dyestuflfrom azo-anthranilic acid phenyZ-p-naphthylamine and ZS-acid A solutionof 21.9 parts of phenyl-pI-naphthylamine in parts of glacial acetic acidis gradually added with vigorous stirring to a tetrazo solution obtainedas in Example VI below from 30 parts of azo-anthranilic acid. Couplingis very rapid and a violet solution is obtained. This solution is addedto a solution of 34.1 parts of the mono-sodium salt of1,8-aminonaphthol-2,4- disulphonic acid in 250 parts of water containing35 parts of anhydrous sodium carbonate. The further coupling gives anintensely blue solution and when complete the dyestufi is precipitatedby adding common salt. It yields bright blue shades on cotton which onafter-treatment with copper sulphate become greener.

EXAMPLE VI Trisaeo dyestufi from azo-anthranilic acid and H-aczd 30parts of azo-anthranilic acid obtained as in Example I or II of theabove-mentioned patent are dissolved in 250 parts of water with theaddition of 10.6 parts of anhydrous sodium carbonate and to the neutralsolution are added 13.8 parts of sodium nitrite. When this has dissolvedthe mixture is cooled to 5 C. and slowly stirred into a solution of 22parts of hydrochloric acid in 100.

parts of water at 5 C. A clear solution of tetrazo compound is obtainedand when tetrazotization is complete it is added to a solution of 68.2parts of the monosodium salt of 1,8-aminonaphthol- 3fi-disulphonic' acid(II-acid) in 300 parts of water containing 53 parts of anhydrous sodiumcarbonate. Coupling is very rapid and results in the formation of a deepblue solution from which the dyestuff is precipitated by adding commonsalt. It is filtered, dried and ground. It dyes cotton in red-blueshades which on aftertreatment with copper sulphate change tobluishgreen. Very similar shades are yielded by the correspondingdyestuff obtained by using, as coupling component the equivalent amountof 1,8- amino-naphthol-2,4-disulphonic acid.

EXAMPLE VII Treatment of dyestufi of Example VI with copper sulphate Tothe finished coupling liquor obtained as in Example VI and withoutprecipitating the dyestufl" formed, sufficient hydrochloric acid isadded to make the reaction neutral to litmus paper. 50 parts of coppersulphate crystals are added and the mixture is then boiled under a.reflux condenser for 2 to 3 hours at the end of which period formationof the copper complex is complete and the solution has assumed agreenishblue tint. 20 parts of anhydrous sodium carbonate are then addedand the mixture is cooled to 15 C. Sufiicient common salt is added toprecipitate the copper complex and this is filtered off, dried andground. It dyes cotton directly in greenish-blue shades.

EXAMPLE VIII Trz'sazo dyestufi from 4,4-diamino-3'-metho:ry-3-carboxy-azo-behzene and 2-amino-8-naphthol-fi-sulphonic acid A tetrazosolution obtained as in Example I from 28.6 parts of4,4'-diamino-3'-methoxy-3- carboxy-azo-benzene is added with stirring toa solution of 52.2 parts of the sodium salt of 2-amino-8-naphthol-6-sulphonic acid in 400 parts of water containing 75parts of calcined sodium carbonate. When coupling is complete thedyestuff is precipitated by adding common salt and isolated byfiltration. It dyes cotton directly in blue-black shades.

EXAMPLE IX Treatment of the dyestufi of Example VIII with coppersulphate 82.5 parts of the dyestuff obtained as in Example VIII aredissolved in 2000 parts of water and boiled with stirring under a refluxcondenser for 4 hours with a solution of parts of crystallized coppersulphate in 200 parts of Water and 200 parts of concentrated aqueousammonia (30%). The copper complex, which partly comes out of solution,is completely precipitated by adding common salt and isolated byfiltration. It dyes cotton directly in a neutral grey shade, fast tolight and washing.

Very similar direct and copper-containing dyestuifs are produced when4,4'-diamino-3'-methoxy-3-carboxy-6-methy1-azo-benzene is used as thetetrazotizable component in Examples VIII and IX in place of4,4-diamino-3'-methoxy-3- carboxy-azo-benzene.

4,4-diamino-3-methoxy-3-carboxy-6'-meth yl-azo-benzene is obtained asfollows:

Production of 4,4-diamino-3'-metho:cy-3-carboxy-6'-methyl-azo-benzene13.7 parts of cresidine (m-amino-p-cresolmethyl ether) are precipitatedin a suitable physical form by dissolving in a mixture of 200 parts ofwater and 10 parts of hydrochloric acid (36%) and adding 10 parts ofsodium bicarbonate. A further 40 parts of sodium bicarbonate are addedand a diazo solution which has been prepared from 18.2 parts of6-nitro-3-amino-benzoic acid by the method described in Example I isadded, keeping the temperature of the coupling mixture at 5 C. Thecoupling is complete in 3 hours. The resulting orange-brown coloredsolution is heated to C. and 36 parts of sodium sulphide nonahydratecrystals are added during one hour at this temperature. It is thenreduced to 15 C. and the 4,4-diamino-3-methoxy-3-carboxy-6-methy1-azo-benzene is precipitated by the addition of sufiicientglacial acetic acid, filtered, washed with water and dried. The productis a dark brown amorphous powder, readily soluble in aqueous alkaliesand in fairly concentrated acids.

EXAMPLE XI Treatment of the dyestufi of Example X with copper sulphate50 parts of copper sulphate crystals are then added to the neutralizedsolution of Example X and the mixture is boiled under a reflux condenserfor 2 to 3 hours, at the end of which period formation of the coppercomplex is complete. Sufficient sodium carbonate is added to make themixture alkaline to litmus paper and the new copper complex isprecipitated by adding common salt. It dyes cotton directly in blueshades of very good fastness to light.

This is a divisional application of U. S. application Serial Number731,568, filed June 20, 1934:.

As many apparently widely different embodiments of this invention may bemade without departing from the spirit and scope thereof, it is to beunderstood that we do not limit ourselves to the specific embodimentsthereof except as defined in the appended claims.

We claim: 1. A compound represented by the formula;

COOH Y in which X is one of a group consisting of hydrogen, methyl, andethyl, Y is one of a group consisting of methoxy and etho-xy, and R is aradical of an amino-naphthol-sulphonic acid coupled ortho to hydroxy.

2. The process which comprises heating with an aqueous solution of aninorganic copper salt the compound represented by the formula:

(IZOOH i in which X is one of agroup consisting of hydrogen, methyl, andethyl and Y is one of a group consisting of methoxy and ethoxy, andcoupling it in alkaline medium to an amino-naphtholsulphonic acid.

3. The step in the preparation of a dyestuff which comprises heatingwith an aqueous solution of an inorganic copper salt a dyestuff of theformula:

EXAMPLE X Trisazo dyesiufi from azo-anthranilw acid and2-N-,6-hydroa:y-ethylamin0-5-naphthol- 7 -s'ulphonic acid The tetrazocompound obtained as in- Example W from 30 parts of azo-anthranilic acidis added to a solution of 61 parts of the sodium salt of 2 N p-hydroxy-ethylamino-5-naphthol-7-sulphonic acid in 300 parts of watercontaining 53 parts of anhydrous sodium carbonate. Coupling results inthe formation of a reddish-blue solution and when complete the couplingliquor is made neutral to litmus paper by means of hydrochloric acid.

4. The compound represented by the formula:

coon Y MORDECAI MENDOZA. FRANCIS LESLIE- ROS-E.

